This is my first time working with thioglycollate broth and based on everything I've found I am not a 100% sure what this type of growth represents. I can see a growth on the top, then a line of no growth and then dispersed growth almost to the bottom of the tube. Would this be typed as facultative anaerobic bacteria?
Hi,
This is most probably facultative anaerobic organism growing. To better distinguish them I would recommenced using 9-10 mL of tioglicolate and keeping the caps loosen during the incubation. In this case you will generate the gradient of oxygen. This will provide you a better separation of aerobes and anaerobes.
Good luck,
P.
I think this is the growth of facultative anaerobes. For more confirmation you can collect the cell residual from the bottom and try to culture them by pour plate method to make ensure they are growing or not....you can also make sure that the bacteria in the bottom is live cell or death..
Ideally this is n outcome of facultatively growing bacteria. To be sure perform Gram staining also to be sure the growth happened because of some type of bacterium.
Aerobic and anaerobic bacteria can be identified by growing them in test tubes of thioglycollate broth: 1: Obligate aerobes need oxygen because they cannot ferment or respire anaerobically. They gather at the top of the tube where the oxygen concentration is highest. 2: Obligate anaerobes are poisoned by oxygen, so they gather at the bottom of the tube where the oxygen concentration is lowest. 3: Facultative anaerobes can grow with or without oxygen because they can metabolise energy aerobically or anaerobically. They gather mostly at the top because aerobic respiration generates more ATP than either fermentation or anaerobic respiration. 4: Microaerophiles need oxygen because they cannot ferment or respire anaerobically. However, they are poisoned by high concentrations of oxygen. They gather in the upper part of the test tube but not the very top. 5: Aerotolerant organisms do not require oxygen as they metabolise energy anaerobically. Unlike obligate anaerobes however, they are not poisoned by oxygen. They can be found evenly spread throughout the test tube.
Thioglycollate is a medium that may be used in two ways: to grow microorganisms under anaerobic conditions, and to test for the oxygen requirement of a bacterium. Added supplements may be added in specific situations, but usually not when testing for the oxygen requirement. It is a differential medium that allows one to differentiate among species according to their oxygen requirements.
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